Fish Aquaculture. Technology and Experiments

242 Pages·1985·27.28 MB·English

by  C. P. B. Meske and F. Vogt (Auth.)

Other Pergamon publications of related interest
PARSONS, TAKAHASHI & HARGRAVE
Biological Océanographie Processes, 3rd Edition
PURCHON
The Biology of the Mollusca, 2nd Edition
RAYMONT
Plankton and Productivity in the Oceans, 2nd Edition
Volume 1 - Phytoplankton
Volume 2 - Zooplankton
FISH AQUACULTURE
Technology and Experiments
by
C H R I S T O PH M E S KE
Federal Research Centre for Fisheries,
Institute for Coastal and Inland Fisheries,
Hamburg/'Ahrensburg, Federal Republic of Germany
Edited and translated by
F R E D E R I CK V O GT
Formerly of the Polytechnic of Central London,
London, UK
PERGAMON PRESS
OXFORD · NEW YORK · TORONTO · SYDNEY · PARIS · FRANKFURT
U.K. Pergamon Press Ltd., Headington Hill Hall,
Oxford OX3 OBW, England
U.S.A. Pergamon Press Inc., Maxwell House, Fairview Park,
Elmsford, New York 10523, U.S.A.
CANADA Pergamon Press Canada Ltd., Suite 104,
150 Consumers Road, Willowdale, Ontario M2J 1P9, Canada
AUSTRALIA Pergamon Press (Aust.) Pty. Ltd., P.O. Box 544,
Potts Point, N.S.W. 2011, Australia
FRANCE Pergamon Press SARL, 24 rue des Ecoles,
75240 Paris, Cedex 05, France
FEDERAL REPUBLIC Pergamon Press GmbH, Hammerweg 6,
OF GERMANY D-6242 Kronberg-Taunus, Federal Republic of Germany
Copyright © 1985 Christoph Meske
All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system or transmitted in any
form or by any means: electronic, electrostatic, magnetic
tape, mechanical, photocopying, recording or otherwise,
without permission in writing from the publishers.
First edition 1985
British Library Cataloguing in Publication Data
Meske, Christoph
Fish Aquaculture.
1. Fish—Culture
I. Title II. Vogt, F.
III. Aquakultur. English
639.3 SH151
ISBN 0 08 024920 5 (Hardcover)
ISBN 0 08 024919 1 (Flexicover)
Printed in Great Britain by A. Wheat on & Co. Ltd., Exeter
EDITOR'S AND TRANSLATOR'S NOTE
As an ex-farm manager I got into fish farming by accident while researching the use of
renewable energies in the bio-industries as a member of Prof Ray Maw's Built Environment
Research Group at the Polytechnic of Central London.
In the process I made a lot of friends: (Dr) Ann M Powell of the City Polytechnic; (Dr)
Alan Starkie of the Severn and Trent Water Authority (who first brought Prof Meske's book to
my attention) and (Dr) Colin Purdom of the Fisheries Laboratory (Ministry of Agriculture,
Fisheries & Food). Unfortunately I met (Prof) John Bardach of the East West Centre and the
University of Hawai too late to avail myself of his kind offer of help.
Without their willing help, advice and constant encouragement I would not have considered
tackling Prof Meske's work nor would I have felt able to do so. I owe them a great debt.
Without Prof Maw's early encouragement this translation would never have gone beyond the
initial stages.
Prof Meske's original book has been updated and augmented and it is fitting here to thank
Pergamon Press, particularly Jill Price, Martin Richardson and John Cooper, for their support
in getting it published.
As an agriculturist I found fish farming a primitive industry which could and should make a
major contribution to the provision of protein for food and job creation for society. These aims
can realistically only be achieved by fundamental changes in the structure of the industry along
the lines of other livestock enterprises and certain arable crops where stock selection,
management, marketing and financing developments have given large gains and stability to
both producers and consumers.
F. Vogt
V
PREFACE
Aquaculture has gained a momentum throughout the world during recent decades which is
probably unparalleled in other branches of food production. Cropping fish and other aquatic
organisms for food is to a large extent based on very old methods. All the traditional methods
together with their modern counterparts are often of high technology and are now commonly
described as aquaculture.
In most countries of the world there is a surge of activity in this field. There are new
research centres, journals, textbooks and many international meetings. All of these confirm the
topical interest in the subject of aquaculture. In recent years it has become clear that the
problems of overpopulation, of food and raw material procurement and of environmental
pollution demand major research work.
This book is an enlarged and updated version of my original work which was first published
by Verlag Ulmer of Stuttgart in 1973.
It describes in Chapters 2 and 3 the methods currently used for the production of those
warm water table fish which are of major importance. The main part of the book — Chapters
4, 5 and 6 — describes the experiments and procedures which may help to combat the growing
food problem through new production methods for animal protein. The aim of the work
presented here concerns the continuous production of warm water table fish independently of
climate or environment within the least necessary space and even in regions with unsuitable
weather or topography.
A large number of experiments were carried out to gain basic knowledge on the
physiological reactions of fish to various environmental influences. In particular the investi-
gations were concerned with the effect of abiotic factors and nutrition on the growth of carp. It
is hoped that this book may be of practical use to commercial fish farmers. Perhaps it will also
make a small contribution towards solving some of the problems of food production and
environmental pollution.
Although the development of a closed cycle or re-circulation system was primarily designed
for experimental work, there was an underlying thought of its possible use in large commercial
enterprises.
vii
viii PREFACE
All the work described in this book was undertaken at Ahrensburg, near Hamburg. During
the early years up to 1970 it took place at the Max Planck Institute for Plant Breeding and
from 1971 onwards at the Institute for Coastal and Inland Fisheries of the Federal German
Fisheries Research Institute.
Although the work reported in this book refers solely to a closed cycle system using the
activated sludge process, this system represents only one of several alternatives. Many centres
throughout the world are working on the development of re-circulation systems and it is
inevitable that this will lead to improved and more economic system performance. As the
availability of clean water tends to decrease, if only regionally, it is difficult to see how fish
farming can be carried on without re-circulation. Fish farming is a growing industry. It demands
an uninterrupted supply of clean water. It would seem that re-circulation systems may be the
only answer.
The work could not have been carried out without my co-workers' unstinting support and
advice with the experiments and the construction and maintenance of the plant.
I thank them all most sincerely for their help, particularly when willingly carried out over
week-ends and throughout the holidays. Without them the research work — and the
publication of this book — would not have been possible. The photographs have been prepared
by Mr K. Engelhardt to whom I express my special thanks.
Finally it is appropriate that I thank the editor and translator for his endeavours.
It is hoped that this book will make a small contribution towards easing the problems of
food production and of pollution.
Ahrensburg 1982 Christoph Meske
1. INTRODUCTION
Fish for human consumption — whether eaten directly, processed or fed to domestic animals
as fish meal — is almost entirely harvested from the seas. In 1980 marine catches amounted to
64.7 million tons (Mt). Inland fishing provided an additional 7.6 Mt of which roughly half was
produced by both salt and fresh water aquaculture. This figure can be broken down into
3.23 Mt of fish, 3.7 Mt of molluscs and 0.71 Mt of crustaceans.
The fishing industry has undergone considerable changes in recent times, relying increasingly
on higher technology, improved methods and more effective gear. Nevertheless it has remained
basically the same: hunting for wild fish in natural waters.
During recent years the problems of the fishing industry have grown considerably. Overfish-
ing has resulted in restrictions and quotas. Almost all coastal states now operate 200 mile (320
km) limits. There are total bans on the fishing of some species, while other previously little or
unknown species have appeared on the market. The bans have affected those countries tradi-
tionally engaged in high seas fishing. As a result joint ventures between the technically advanced
nations and the underdeveloped countries have been inaugurated in the fields of research, pro-
cessing and marketing.
Apart from overfishing there is also the problem of pollution of which oil slicks and toxic
industrial waste effluent are examples. In recent oil rig disasters large quantities of oil were dis-
charged into the sea. There have been several major tanker accidents. In Japan industrial dis-
charge caused a new medical condition.
A number of other factors influence the fish crop adversely. Cannibalism, parasites, viral and
bacterial infection occur naturally. As the natural balance is upset by man-made changes in the
environment the consequential and cumulative effect may have serious repercussions on the
world's food supply.
ι
2 FISH AQUACULTURE
OVERFISHING
The history of post-war fishing is one of increasing catches. In the 11 years from 1957 to 1968
catches roughly doubled and rose from 40 Mt a year in 1960 to 63.3 Mt a year in 1968. The first sign
of a turndown appeared in 1969 when there was a 1.2 Mt or 2% reduction in the catch on the
previous year.
Up to this time it was thought that the global crop would continue to increase at the same
rate as before. Catches rose as fishing fleets equipped themselves with more advanced technical
aids and gear, while at the same time reducing the chances of the fish population to regenerate
itself. Between 1969 and 1974 the fishing fleet grew by over 50%, consisting of larger vessels
and factory ships. It is open to debate whether the arrest in the crop yield during this period
is due to the expansion of the fleet, or whether even the greater number of ships were unable to
raise the level of catches (Table 1).
TABLE 1.
World Catches 1956-1980 (FAO) in million metric tonnes
1956 30.5 1968 64.3
1958 33.2 1970 69.5
1960 40.0 1972 65.5
1962 46.9 1974 70.3
1964 52.8 1976 69.6
1966 57.4 1978 70,4
1980 72.3
The FAO made an optimistic forecast of improving catches rising to 130 Mt a year in the
year 2000. This figure is open to doubt, particularly as the increasing sophistication of the
equipment is likely to expose the residual population in the coastal water of the developing
countries to the dangers of overfishing. Table 1 shows that world fish catches have not risen to
any extent during the last 10 years.
When Iceland first imposed its 50 mile (80 km) fishing limit there was considerable diplo-
matic activity followed by the cod war with the United Kingdom. The International Court at
The Hague was unable to exert its authority. Since then 200 mile (320 km) fishing limits have
become the norm and the smaller seas, like the Baltic, have been divided among bordering
states. The stress caused within the European Economic Community (EEC) over national or
traditional fishing rights gives an indication of the political importance now given to fishing.
The freedom of the seas is being less frequently mentioned.
Fishing has until now been based exclusively on economic criteria while neglecting biology
and the environment. The very profitable but biologically lethal exploitation of the cod
spawning shoals is an example, as is the catching of immature herring for feeding to trout. It
should be noted that it takes 6 kg of wet herring to produce 1 kg of trout. As a result of over-
fishing there was for a period a total ban on catching herring in the North Sea except for fish
for direct human consumption in Danish coastal waters (Table 2). While total world catches
INTRODUCTION 3
TABLE 2.
North Sea herring Catches in million tons
1965 1.2 1977 0.084
1975 0.313 1978 0.030
1976 0.190 1980 nil
remained steady there was a rapid decline in the anchovy crop from the west coast of South
America. Anchovy catches off Peru dropped from its place as the leading fishmeal producer
with 2.25 Mt in 1970 to fourth place with only 0.44 Mt in 1977. The disappearance of the
anchovy is attributed partly to a change in the Humboldt current and partly to overfishing.*
Peru consequently introduced conservation measures. Globally fish meal production fell by
9.5% between 1976 and 1977. Fish meal remains the most important component in compound
feeds for pigs, poultry and table fish.
While the dangers of overfishing have been generally accepted, conservation measures have
been slow in being implemented. There are now international agreements on closed seasons,
regional quotas and total bans covering some of the important species of fish. Controlled pro-
duction and rearing of marine fish for seeding the seas may lead to a slow rise in the yields,
provided that the research work now being carried out at many centres is stepped up. Through
controlled management, feeding and rearing of marine fish a bridge between fishing and aqua-
culture can be established. Work in this relatively new research field appears to be most ad-
vanced in Japan where there is a plan to convert large areas of inland seas into the equivalent
of meadows in which stock can graze. The basis of this plan rests on the considerable successes
Japanese workers have had with the controlled production of salt water fry such as red sea
bream (Chrysophrys major), shrimp and mollusc larvae. The project also includes pathology and
genetics.
Japan has the advantage of a coast with many bays. This allows large areas of sea to be ex-
ploited by planned developments. Similar schemes in less-favoured locations are likely to be-
come important in the future. The successful work on flat fish carried out in Great Britain and the
culture of salmon in Norway are indications of what can be achieved.
POLLUTION
Both marine and fresh water fish are increasingly exposed to toxic matter arising directly or
indirectly from man-made industrial waste, both sea- and land-borne. This includes industrial
* Editor's note: The recurring Pacific El Nino weather system alters the weather and currents of the region.
The El Nino storms of 1972 are thought to have wiped out nearly 90% of the anchovy fishing industry along
the South American coast. The anchovy population might have recovered but for the excessive fishing. In
1982/83 the system is assumed to have been responsible for the population crash affecting 17 million birds —
terns, shearwaters, frigates and other species. The birds abandoned their nesting sites when their food sources
failed. The El Nino changes were first described by Sir Gilbert Walker of the Indian Weather Service some 50
years ago. He called them southern oscillations.
4 FISH AQUACULTURE
effluent, sewage discharged into rivers, lakes and the sea as well as bilge. The discharge may be
continuous or sporadic and the effect of the pollution on commercially exploited fish can be
divided into three groups:
1. Sudden wipe-out of the fish from acute poisoning due to the addition of large amounts of
highly toxic substances.
As an example the River Rhine disaster of 1969 can be cited. Fish deaths were catastrophic.
Initially it was presumed that an insecticide, toxaphene, was the cause, but its connection
with the disaster remained unproven. Many similar cases are being reported without the
cause being determined in the majority of cases. The drainage or leaching from farmed land
is known to be responsible for cases of wipe-outs in rivers and lakes. American work indi-
cates that mixtures of certain chemicals are often considerably more lethal than component
substances alone (Marking and Dawson, 1975).
2. The effect of toxic substances on eggs and larvae.
This is of special importance in coastal waters in which commercially important fish tend to
develop but where they are exposed to fluvial detritus. During the early stages of life fish —
like all higher organisms — are particularly susceptible to toxicity (Goetting, 1971). De-
struction at this stage has a rapid effect on the size of the fish population although when
adult these fish may be tolerant to a certain low level of toxicity.
3. Storage of toxic substances at sub-lethal levels in commercial fish.
Best known examples are the accumulation of mercury and insecticides such as DDT. Again,
arising from industrial and agricultural pollution these substances are carried in the rivers to
the sea where they enter the food chain via plankton. Eventually they end up in carnivores,
such as the tunny, swordfish and pike, as well as in birds of prey, such as the sea eagle, and
mammals, e.g. seals. In the case of organomercuric compounds high concentration is rapidly
achieved because carnivores find it easy to catch affected fish whose responses are impeded
by the poison. These carnivores often have high contamination levels as a consequence.
A sick seal caught in Lake Saimaa in Finland had a muscular mercury content of 197 ppm
(Nuorteva, 1971). In southern California seals were found to have up to 700 ppm of mer-
cury in their livers (Anas, 1974). Among marine fish the swordfish (Xiphias gladius) and
the marlin (Makaira indica) appear to be the species most contaminated by mercury with an
average of 7.3 ppm intramuscular mercury (MacKay et al, 1975). The permissible limit in
the USA and Canada is 0.5 ppm.
The first recorded case of human disease and deaths caused by consumption of mercury-
contaminated fish occurred in Japan: Minamata Disease. The fish eaten contained 10 ppm of
mercury and drew attention to heavy metal contamination (e.g. Pearson and Frangipane, 1975).
In Europe too, especially in Scandinavia, high mercury values were observed in fish. Although
no lethal cases were reported high concentrations of this metal were found in the blood and hair
of people eating a lot of fish. Pike caught in several Finnish rivers contained mercury far above
the limits of tolerance.
Apart from the heavy metals — mercury, lead, cadmium, chrome, zinc, nickel and copper —
the following toxic residues in fish are of particular importance: non-metallic trace elements,